About this replacement
Lenovo K6 Note / K8 Plus — 3.8V Li-Polymer Replacement Battery (BL273)
This is a 3.8V, 3750mAh (14.25Wh) lithium-polymer battery for the Lenovo K6 Note, K6 Note Dual SIM, and K8 Plus. It replaces OEM part number BL273 directly. Use it when the original cell no longer holds a charge or causes unexpected shutdowns.
- K6 Note and K8 Plus compatibility: Both devices run the same 3.8V battery rail and use the same BL273 connector footprint and BMS handshake protocol — one cell covers all three variants listed.
- Bench tested on actual hardware: We cycled the cell through full charge and discharge on a K6 Note unit. The BMS accepted the cell without error, voltage held steady through the mid-range discharge curve, and the charge IC completed a full cycle without flagging a fault.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging begins — skipping this step causes the OS to report inaccurate percentages for several days.
Sudden shutdown at 20–30% on the K6 Note after a cell swap
This happens because the fuel gauge IC is still calibrated to the old cell's voltage-to-capacity curve. The new cell hits its voltage cliff at a different point, so the phone cuts power before the OS registers empty. The modem and display together draw enough current during peak load to pull the terminal voltage below the BMS cutoff threshold even when the gauge still shows charge remaining. One full discharge-charge cycle with fast charging off re-anchors the coulomb counter to the new cell.
Phone won't power on after the BL273 sat in storage
Lithium-polymer cells in storage self-discharge slowly. If the cell dropped below approximately 2.5V per cell, the BMS enters a lockout state and blocks normal charging to prevent thermal runaway on a deeply depleted cell. Connect the phone to a wall charger — not a USB port — and leave it for 20–30 minutes without pressing the power button. Most BMS controllers on this platform will accept a trickle pre-charge at that point and exit lockout once the cell recovers to around 3.0V.